The present invention relates to a dumbbell with a base assembly, where, at each end of a handle, there are securable a selectable number of weight disks standing upright in the base assembly, the weight disks having through-going openings which are disposed in alignment with one another, when the weight disks stand in the base assembly, and the weight disks have mutually cooperating connecting means which are disposed, in the axial direction of the dumbbell, to interconnect neighbouring weight disks, but in a radial direction to permit separation of one weight disk from a neighbouring weight disk, and the handle having pin members projectable in opposing axial directions and insertable into the weight disks, whereby, by selection of the axial projection lengths of the pin members, the number of weight disks on the dumbbell is selectable.
U.S. Pat. No. 6,416,446 discloses a dumbbell which comprises a base unit or assembly with two sets of weight plates which are nestable in the base assembly, standing upright on edge. Between the weight plates there is disposed a handle, with pins extendable in opposing axial directions.
The weight plates have connecting means which are formed in such a manner that they interconnect, in the axial direction, neighbouring weight plates, but permit a radial displacement between two neighbouring weight plates.
The handle has a U-shaped central section with a bottom plate, in which gears are disposed for projecting the above-mentioned pins or rods.
The weight disks are complex in configuration and asymmetric, which implies that the total point of gravity of the dumbbell will probably be far away from a central, longitudinal axis through the dumbbell. What is more serious is that the U-shaped handle presents a major risk factor, since the bottom portion of the handle, where the gears are accommodated, could strike the wrist of a user and injure the wrist, if the dumbbell were inadvertently to rotate in the user's hand. Furthermore, in certain embodiments, the weight disks at opposing ends of the dumbbell are united by the intermediary of interjacent rods which, naturally, also in themselves constitute a risk factor and which moreover make the dumbbell extremely uncomfortable to use.
A similar, and just as clumsy and hazardous a dumbbell is shown in U.S. Pat. No. 650,101.
It is desirable to improve the dumbbell described by way of introduction such that the drawbacks inherent in the prior art technology are obviated. In particular, it is desirable to design the dumbbell so that there are no risks of injury regarding the wrist of the user and, naturally, the dumbbell will be comfortable to use. Further, it is desirable to design the dumbbell so that the point of gravity of the dumbbell in the circumferential direction will be somewhere along the longitudinal centre axis of the dumbbell, and finally that the dumbbell will be simple and economical to manufacture.
According to an aspect of the present invention, the dumbbell intimated by way of introduction is characterised in that the handle, at opposing ends, has connecting means for cooperation with the connecting means on the mutually most proximally located weight disks in the base assembly, that the space between the connecting means is free through 360° about the handle throughout the entire length thereof, and that the weight disks have through-going openings centrally located.